Device for tempering preforms and tempering method

ABSTRACT

The process is used for tempering preforms made of a thermoplastic material; the preforms are to be blow molded. The preforms are provided with a temperature profile along a circumference. The temperature profile is generated by differentially heating strip-shaped regions, which extend in the direction of a longitudinal axis of the preform. A step-by-step tempering for the purpose of temporally sequential thermal conditioning of different regions of the preform is carried out with movement phases and rest phases. A carrier device is rotated by the interactions of a gear and a matching gear for initiating rotational movements. The preform is moved, motionless with regard to the rotational direction, through the tempering zone at least along a portion of the transport path before the start of the engagement of the gear with the matching gear.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention concerns a process for tempering preforms made of athermoplastic material, where the preforms are intended to beblow-molded into containers and where the preform is provided with atemperature profile along a circumference, which is generated bydifferentially heating strip-shaped portions, which extend in thedirection of a longitudinal axis of the preform, and where step-by-steptempering for the purpose of sequential thermal conditioning ofdifferent regions of the preform is implemented, and where step-by-steprotation with a motion phase and a rest phase is carried out as well.

The invention further concerns a device for tempering preforms made of athermoplastic material, which includes at least one transport path forthe preforms and at least one heating device, and which provides thepreforms with a temperature profile in the circumferential direction andwith at least one rotational drive unit for carrying out a rotationalmovement of the preform, which generates a step-by-step rotationalmotion of the preforms.

Such a process is used, for example, when containers are to be producedwhose cross-sections deviate from a circular shape. The deviation can,for example, consists of producing containers with an oval cross-sectionor, for example, with a triangular or a rectangular cross-section.

The production of such non-rounded containers was already described inU.S. Pat. No. 3,775,524. At first, a symmetrical tempering of thepreforms occurs, then the temperature in selected regions is selectivelyincreased. Further variants of temperature profiling of the preform in acircumferential direction are also described in U.S. Pat. No. 3,632,713,U.S. Pat. No. 3,950,459 as well as in U.S. Pat. No. 3,892,830. Atemperature conditioning process by selective shading is presented inDE-OS 33 14 106.

From U.S. Pat. No. 5,292,243 it is known to simultaneously subject twopreforms to temperature conditioning in the circumferential direction.In EP-OS 0 620 099 a compilation of processes for temperatureconditioning known from the state of the art can be found. Astep-by-step rotary motion of the preforms during temperatureconditioning is explained in PCT-WO 97 32 713.

The previously known individual processes have a number ofdisadvantages, for example, a relatively high apparatus cost isincurred, only a relatively poor reproducibility can be ensured, or,according to the device of the last-mentioned publication, theproduction volume per unit time is limited.

It is, therefore, the objective of the present invention to present aprocess of the kind mentioned in the introduction in such a manner thata high-quality temperature conditioning process can be achieved at ahigh rate of production.

This objective is achieved according to the invention in that thepreform is transported by a carrier device through a tempering zone,that the carrier device is given a rotary motion by engaging a gear forthe initiation of rotary motion, which engages a matching gear and thatthe preform is moved at least along a portion of the transport pathbefore the gear engages the matching gear, and is moved at least along afurther portion of the transport path through the tempering zone afterthe interaction between the gear teeth has stopped without motionrelative to the rotational direction

It is a further objective of the present invention to design a device ofthe previously mentioned type in such a manner that a selectivetempering of the preform can be achieved at a high rate ofreproducibility and a high rate of production.

This objective is achieved according to the invention in that a carrierdevice for the preforms includes a control element, which is disposedeccentrically relative to a longitudinal axis of the carrier device,which can be positioned by a radial cam and which provides positioningof the preform in the direction of rotation, and that the radial cam hasat least two cam segments along the transport path, which are parallelto the transport path, as well as at least two cam segments, which aretransverse to the transport path.

The step-by-step tempering of a preform makes it possible, for example,to dispose common radiant heaters according to the state of the artalong with IR-radiators along a transport path-of the preform and toexpose different regions of the preform to the radiation for differentperiods of time. In this case in particular no costly coordinationbetween the velocity of a longitudinal movement in the transportdirection and the speed of rotation is required.

The arrangement of the preform on a carrier device during the heatingprocess makes it possible to allow the forces for carrying out thepositional changes and for generating the transport velocity to onlyindirectly affect the preform. The preform can be disposed at leisurerelative to the carrier device, and all movements are generated by theinteraction of functional elements with the carrier device. Thisfacilitates a protective handling of the preform, which has beenplasticized by the tempering process. By generating the rotary motion inaccordance with the process according to the invention by means of theinteraction of a gear with a matching gear, a very high flexibility inthe setting of the motion sequences is achieved. Moving the preformthrough sequential phases of a gear engagement and the translationalphases of the preform without rotary movements supports the generationof the required temperature profile in the circumferential direction.

The radial cam contemplated according to the device of the invention forpositioning the carrier device, facilitates the implementation ofposition changes of the preform in the direction of rotation without anyactive actuating elements, but merely by tracking the radial cam duringthe implementation of the forward motion of the preform. The use ofradial cams and associated control elements at the carrier device leadsto an exact reproducibility of the rotational positioning actions andavoids deviations from the required positioning which increase along thetransport path.

In order to support a space-saving process implementation it is proposedthat the preform be transported along a curved heating path.

A simple transport process in the region of the heating device can beachieved by having the preform transported in the region of the heatingdevice by a heating wheel.

For providing a thermal basic conditioning it is proposed that thepreform, in an initial region of the heating path, be at firstcontinuously rotated for providing it with a basic tempering.

A further possibility for carrying out a part of the rotary movementconsists in positioning the carrier device in a guide rail in therotational direction by the action of a control element.

An effective initiation of positioning forces can be accomplished byintroducing lever-like positioning forces by means of the controlelement into the carrier device.

A mechanical establishment of a given rotational positioning issupported in that the carrier device, along at least a portion of thetransport path, is moved by means of a transversely forwardly orientedlever-like control element.

It also proves to be advantageous that the carrier device is moved alongat least a portion of the transport path by means of a transverselyrearwardly oriented lever-like control element.

To facilitate a tempering of the wall regions, which are relativelyuniform with respect to each other, it is proposed that when the gearteeth engages the matching gear, as well as during an interactionbetween the control element and the guide rail, a common rotationaldirection of the carrier device be maintained.

However, alternatively it is also possible that the carrier device, whenthe gear engages the matching gear, be rotated in the opposite directionto that of an interaction between the control element and the guiderail.

The rotational positioning actions can be achieved at a low degree offriction by providing the control element with a cam roller.

In order to facilitate a modular implementation of the heating device itis proposed that the heating device include heating boxes, which areequipped with infrared radiators.

A spatially effective arrangement of the individual components consistsin placing the matching gear between two heating boxes.

In order to achieve an optimum utilization of the available space it isproposed that the heating boxes be placed relative to the transport pathof the preforms at the outside along the heating wheel.

An advantageous realization of the carrier device consists in designingthe carrier device as a transport rod, which includes a holding devicefor the preforms.

In order to provide rotational positioning of the preforms as well as ofthe blow-molded bottles, which is always spatially exact, it is proposedthat at least along a portion of the transport path of the preformsoutside the region of the heating devices, a radial cam for the controlelements be provided.

A further variant for handling the preforms consists in providing radialcams for the control elements, except for the transport path of thepreforms through the blow-molding device as well as in the region of auniform rotation of the preforms along the heating device and alongother regions of the transport path of the preforms through the devicefor blow-molding.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing, examples of embodiments of the invention are shownschematically. The figures show the following:

FIG. 1 is a simplified presentation of a device for blow-molding withheating wheel and blow-molding wheel, in accordance with the presentinvention.

FIG. 2 is a presentation of a further device for blow-molding in anotherstrongly schematized embodiment with rail-like guide elements for thecarrier device along regions of the transport path also in accordancewith the present invention.

FIG. 3 a magnified presentation of a heating wheel of FIG. 4 withassociated heating boxes and cooling blowers,

FIG. 4 is an enlarged a presentation of a carrier device for the preformshown in FIG. 3 with a control element and an associated radial cam,

FIG. 5 is a presentation of the carrier device of FIG. 4 shown duringthe engagement of a gear of the carrier device with a matching gear,

FIG. 6 a simplified presentation looking in the direction of arrow VI ofthe carrier of FIG. 5 as viewed.

FIG. 7 is a further schematized presentation illustrating theinteraction of a control element with the radial cam to effect a changein direction and

FIG. 8 is a further presentation illustrating the shape of the radialcam along the transport path of the preform in the region of the heatingdevice.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the case of the embodiment shown in FIG. 1, the device forblow-molding containers includes a heating wheel (1) and a blow-moldingwheel (2). The preforms to be processed are guided via a supply rail (3)into the region of a turning device (4) and transported by the transferwheels (5, 6, 7) into the region of the heating wheel (1). In thisvariant, the preforms are guided along the supply rail (3) hanging withtheir openings pointing upwardly, and they are turned by the turningdevice (4) by 180°. Heating in the region of the heating wheel (1) thusoccurs in such a manner that the preforms are standing with theiropenings oriented downwardly. But it is also conceivable to carry outheating in the hanging orientation without a preceding turning of thepreforms.

Along the heating wheel (1) there are heating devices (8) and coolingdevices (9). The heating devices (8) heat the preforms with the aid ofIR-radiation, and the cooling devices (9) blow air upon the surfaces ofthe heated preform in order to cool them.

After completion of the heating process and after passing through acooling region, the tempered preforms are transported from a transferwheel (10) to the blow-molding wheel (2) and are here placed in forms(11), which are held in place by the blow-molding stations (12). Theblow-molding stations (12) can be opened and closed like books. Aftercompletion of the blow-molding process, the blow-molded containers areremoved from the blow-molding station (12) and are moved to a releasepath (15) by transfer wheels (13, 6, 14). In the case of blow-moldingthe preforms in the region of the blow-molding wheel (2) with theopenings oriented downwardly, it is in particular contemplated to placea further turning device between the blow-molding wheel (2) and therelease path (15), so that the blow-molded containers can betransported, while hangingin an upright position, in the region of therelease path (15).

The preform consists typically of an opening section, a support ringseparating the opening section from the neck region, a shoulder regionblending into a wall section as well as a bottom. The support ringextends across the opening section transversely to a longitudinal axis.In the area of the shoulder region the outer diameter of the preformwidens starting with the neck region.

The opening section can, for example, be equipped with an outer thread,which makes it possible to add a screw closure to the finishedcontainer. But it is also possible to equip the opening with an outerlip in order to generate a surface of attack for a crown cork. Beyondthis, a multiplicity of further configurations is conceivable in orderto facilitate the addition of plug-type closures.

From the presentation in FIG. 2 it can be seen that along the transportpath of the preforms guide rails (16) are disposed, which provide theexactly defined orientations of the preforms in the direction ofrotations in the region of the particular transport positioning. Thiscan, in particular, ensure that the preforms, which have been providedwith the temperature profile in the direction of the circumference inthe region of the heating wheel (1) are transferred to the blow-moldingstations (12) in the region of the blow-molding wheel (2) in a preciselyknown and established orientation. By this means a precisely definedallocation of the circumferential regions of the preforms to the contourof the forms (11) is achieved.

From FIG. 2 it is likewise recognizable that at least some of thetransfer wheels (7, 10, 13) are equipped with transfer arms, whichposition the preforms or the blow-molded bottles.

From the enlarged presentation of the heating wheel (1) in FIG. 3 it canbe seen that in the direction of transport (17) at first two relativelywide heating devices (8) are arranged and that the subsequent heatingdevices (8) are smaller in the direction of transport. It is alsorecognizable that always between two heating devices (8) cooling devices(9) are located, which are constructed as blowers. Likewise one or moreblowers (9) are provided in the direction of transport (17) behind thelast heating devices (8). Along order to improve the life expectancy ofthe heating devices (8), the heating devices (8) themselves are equippedwith blowers (18).

The presentation in FIG. 4 illustrates an engagement of a carrier device(19) for the preforms, or, as the case may be, the blow-moldedcontainers, with a control element (20) in the guide rail (16). Thecontrol element (20) is thus designed to include a cam roller (22),which is eccentric with respect to a longitudinal axis (21) of thecarrier device (19). As a guide rail (16), for example, a U-shapedprofile can be used, which guides the cam rollers (22) in the region oflateral legs (23, 24).

The carrier device (19) can be constructed as a transport rod, whichfeeds compressed air through an interior space to the preforms to beexpanded in the region of blow-molding station (12).

According to the embodiment shown in FIG. 4 the carrier device (19) isprovided with a gear (25), which can be constructed as a centrallylocated gear relative to the longitudinal axis (21). The gear isnon-rotatably attached, to the carrier device (19).

From the presentation in FIG. 3 each positioning of the carrier device(19) with control element (20) in various orientations can be seen.Preferably, the eccentrically placed control element (20) is orientedafter completing a rotary movement in the direction of transport (17),oriented either transversely forward of or transversely rearwardly ofthe direction of transport 17.

FIG. 5 shows the carrier device (19) in a transport position, where thecontrol element (20) is released from a guide rail (16). In thisposition, however, the gear (25) engages a matching gear (26), which issup ported by of a support (27). In the embodiment shown, the matchinggear (26) is attached as a rack segment or as a chain section to of thesupport (27). A rotary movement of the carrier device (19) is thuscaused only by the translation of the carrier devices (19) in thedirection of transport (17) and by the associated rolling motion of thegear (25) against the matching gear (26).

According to another embodiment, however, it has also been contemplatedto make the matching gear (26) moveable. By means of this moveablearrangement of the matching gear (26), an active propulsion of thecarrier device (19) in a circumferential direction can occur, in orderto deliberately accelerate the rotational speed as opposed to a simplerolling action, or if need be, to slow it down as well.

FIG. 6 shows a further possible embodiment of the matching gear (26).Here the elements for engaging the gear (25) are constructed ascylindrical segments and are given a distance from each other, which isadapted to the contouring of the gear (25).

The detailed presentation in FIG. 7 illustrates the engagement of thecontrol element (20) with the guide rail (16) in the region of a plannedposition change of the carrier device (19) in the circumferentialdirection. In the positioning of the transport device (19) shown, thecontrol element (20) is oriented transversely forwardly of the transportdirection (17) and bumps against a deflection flank (28) of the guiderail (16). Opposite to the direction of transport (17), the deflectionflank (28) blends into a deflection depression (29), in the region ofwhich one width of the guide rail (16) becomes greater relative theother widths of the guide rail (16). This enlargement makes it possiblefor the control element (20), following its contact with the deflectionflank (28), to carry out a movement in the direction of the turn (30)during a further translational movement of the carrier device (19) inthe transport direction (17).

The rotational movement of the carrier device (19) in the direction ofthe turn (30) is at first continued until such a time when theconnecting line between the control element (20) and the longitudinalaxis (21) is essentially directed transversely to the transportdirection (17). When the translational movement of the carrier device(19) is continued in the transport direction (17), the control element(20) slides along a diagonal segment (31) of the guide rail (16) andthus results in a further turning of the carrier device (19) in theturning direction (30). This rotational movement will be continued untilthe control element (20) again enters the region of a segment (32),which extends essentially parallel to the transport direction (17). Thenthe position of the carrier device (19) shown in FIG. 6 will once againbe assumed.

FIG. 8 illustrates a combination of segments of the guide rail (16) andthe arrangement of matching gear (26). According to the embodimentshown, in the direction of transport (17) alternating segments of guiderails (16) and deflection depressions (29) are shown behind one anotherand between these segments matching gear (26) is disposed. In oneorientation opposite to the direction of transport (17) a segment of theguide rail (16) begins always with an entry region (33), which becomessmaller, like a funnel, in the direction toward a first diagonal segment(31). By means of this funnel-like reduction of the entry region (33),any possible deviations of the orientation of a connecting line of thecenters of the control element (20) and the carrier device (19) arecompensated. By means of the diagonal segment (31), the control element(20) is oriented transversely forwardly in the transport direction (17).

In the turning depression (29) a reorientation occurs and a return tothe starting position takes place after leaving the segment (16) in theregion of the matching gear (26). In principle, it is possible toprovide for a continuation in the region of the matching gear (26) ofthe rotational direction of the carrier device (19) as defined by thepath of the guide rail (16), but it is equally possible to provide arotational direction which is opposite to the original rotationaldirection, and by this means to cause a return to the original position.However, in principle, a continuous maintenance of the of the rotationalorientation is preferred in view of the highest possible uniformity andreproducibility.

According to the embodiment shown in FIG. 8, the segment of the guiderail (16) also includes a disengagement region (34), which becomeslarger in the transport direction (17). Due to this enlargement in thedisengagement region (34), it is possible to provide for a spatiallytight arrangement of the segments of guide rail (16) as well as of thematching gear (26), and in spite of a spatial superimposition of thecontrol element (20) upon the disengagement region (34) to already causea rotational movement of the carrier device (19).

For a further improvement of the technical effects, which have alreadybeen described in principle, different variations are conceivable. Forexample, for a secure fastening of the preform in the region of thecarrier device (19) it is possible to provide a clamping ring disposedin the region of the carrier device (19). In order to carry out therequired movements it is also advantageous in the case of thearrangement shown in FIG. 3, not only to provide for a rolling off ofthe two first—in the transport direction (17)—heating devices (8) of thecarrier devices (19) with their gear (25) at a stationary, matchinggear, but to provide here as a matching gear, for example, a drivenchain. As compared to a simple rolling off at a stationary matchinggear, by this means, the rotational velocity can, for example, bedoubled.

Alternatively to a permanent control of the rotational positioning ofthe carrier device (19) outside the region of the heating wheel by aninteraction of the control elements (20) with the guide rail (16), it isalso possible not to provide the rotational orientation, at least for aregion, and to provide a defined determination of the rotationalorientation of the carrier devices (19) only before a transfer to theblow-molding station (12) or before a transport of the carrier devices(19) along the heating devices (8) by means of suitable guide elements.

In order to implement the temperature profile in the direction of thecircumference of the preform, it is, for example, possible to carry outa rotation of the preform (1) around the longitudinal axis (8) with astep-by-step movement in such a manner, that always short movementsections and rest sections follow one another. In the case oftemperature profiling in the circumferential direction with four angularregions, the movement can occur in such a manner, that at first, withina predeterminable rest section, a predeterminable angular region of thepreform is turned toward the heating device (8), and that at the end ofthe rest section within the movement section, a subsequent angularregion is moved relatively rapidly past the heating device (8). At theend of the second movement section, the second angular region is nowfacing the heating device (8). The preform will thus be rotated by 180°.The duration of the movement sections is normally made much shorter thanthe duration of the rest section.

For example, it is also possible to initially temper the preformuniformly and to generate the temperature profile subsequently with thehelp of the movement of the temperature profile described. It is alsopossible to provide for a movement of the preform during its rotation insuch a manner, that, starting with a cold preform, the temperatureprofile is achieved by the different phases of movement. At least in thecase of a temperature profiling, which follows an initial tempering, themovement sections are temporally much shorter than the rest sections.The ratio of the durations can, for example, be 1:10.

The measures described for the generation of a temperature profile inthe region of the preform in the direction of its longitudinal axis aswell as in the circumferential direction can be arbitrarily combined, sothat an adaptation to the various actual preform geometries can beachieved.

In principle, any thermoplastic materials can be processed according tothe described process and with the help of the described device. Inparticular, it is possible, for example, to process preforms ofpolypropylene or polyethylene terephthalate.

In view of the diverse possibilities described for tempering thepreform, where the preform is at first uniformly tempered in the regionto be tempered and then given a superimposed temperature profiling, itshould be added that this tempering process can also be applied in thecircumferential direction of the preform as well as in the longitudinaldirection of the preform or with both spatial orientations combined. Theheat profiling in the longitudinal direction is, furthermore, chosenespecially in such a manner, that a high and uniform orientation of thematerial is achieved, in order to be able to ensure a strong blow-moldedcontainer as well as a low material consumption.

As an alternative to the use of a heating wheel in the region of theheater (8), it is, for example, also possible to carry out a transportof the preforms with the help of a drive chain. The correspondingelements for positioning the carrier devices (19) are in this casedisposed along the transport chain. The transport chain can, forexample, be placed along a rectangular base structure and be turned atcorner regions of this base structure by means of rollers or gears. Anarrangement of the heating devices (8) in the case of using a transportchain is preferably along linear regions of the transport chain. Inprinciple, however, it is also possible to move the transport chainalong a curved path.

We claim:
 1. A process for tempering preforms made of a thermoplasticmaterial, where the preforms are intended to be blow-molded intocontainers and where the preform is provided with a temperature profilealong a circumference, which is generated by differentially heatingstrip-shaped portions, which extend in the direction of a longitudinalaxis of the preform, and where a step-by-step tempering for the purposeof temporally sequential thermal conditioning of different regions ofthe preform is implemented, and where step-by-step rotation with amotion phase and a rest phase is carried out as well, characterized inthat the preform is transported by a carrier device (19) through atempering zone, that the carrier device (19) is given a rotationalmovement by the engagement of gear (25) with matching gear (26) forinitiating rotational movements, and that the preform is moved at leastalong a portion of a transport path prior to the engagement of gear (25)with matching gear (26) and at least along a further part of thetransport path after the termination of the engagement of the gear (25)with the matching gear (26) and that it is moved through the temperingzone without movement with respect to the rotational direction.
 2. Aprocess according to claim 1, characterized in that the preform istransported along a curved heating path.
 3. A process according to claim2, characterized in that the preform in the region of the heating device(8) is transported by a heating wheel (1).
 4. A process according toclaim 1, characterized in that the preform, in an initial region of theheating path, at first continuously rotates in order to be subjected toa basic tempering process.
 5. A process according to claim 1,characterized in that the carrier device (19) is positioned in thedirection of rotation by the interaction of a control element (20) witha guide rail (16).
 6. A process according to claim 5, characterized inthat by the control element (20), in a lever-like manner, positioningforces in the direction of the carrier device (19) are initiated.
 7. Aprocess according to claim 1, characterized in that the carrier device(19) is moved along at least a portion of the transport path by means ofa lever-like control element (20), which is oriented transverselyforwardly.
 8. A process according to claim 7, characterized in that thecarrier device (19) is moved along at least a portion of the transportpath by means of a lever-like control element (20), which is orientedtransversely rearwardly.
 9. A process according to claim 8,characterized in that during an engagement of gear (25) with matchinggear (26) as well as during an engagement of the control element (20)with the guide rail (16) a common rotational direction of the carrierdevice (19) is maintained.
 10. A process according to claim 8,characterized in that during an engagement of gear (25) with matchinggear (26) the carrier device (19) is moved in the opposite direction asduring an engagement of the control element (20) with the guide rail(16).
 11. A device for tempering preforms made of a thermoplasticmaterial, which includes at least one transport path for the preformsand at least one heating device which provides the preforms with atemperature profile along a circumference, and where at least onerotational drive unit is provided for carrying out the rotationalmovement, which produces a step-by-step rotational movement of thepreforms, characterized in that a carrier device (19) for the preformsthrough a tempering zone, that the carrier device (19) has a controlelement (20), which is eccentrically positioned relative to alongitudinal axis (21) of the carrier device (20), which can bepositioned by a radial cam, and which determines a positioning of thepreform in the rotational direction and that the radial cam along thetransport path of the preform contains at least two cam segments, whichare parallel to the transport path as well as at least two cam segmentswhich proceed transversely to the transport path.
 12. A device accordingto claim 11, characterized in that the control element (20) includes aradial cam (22).
 13. A device according to claim 11, characterized inthat the heating device (8) has heating boxes, which are equipped withinfrared radiators.
 14. A device according to claim 11, characterized inthat the carrier device (19) includes a gear (25).
 15. A deviceaccording to claim 14, characterized in that in the region of theheating device (8) a matching gear (26) is provided which corresponds togear (25).
 16. A device according to claim 15, characterized in that thematching gear (26) is disposed between two heating boxes.
 17. A deviceaccording to claim 11, characterized in that the heating device (8)includes a heating wheel (1) for transporting the preforms.
 18. A deviceaccording to claim 17, characterized in that the heating boxes areplaced on the outside along the heating wheel (1) relative to thetransport path of the preforms.
 19. A device according to claim 11,characterized in that the carrier device (19) is designed as a transportrod, which includes a retaining means for the preforms.
 20. A deviceaccording to claim 11, characterized in that at least along a part ofthe transport path of the preforms outside the region of the heatingdevice (8) a radial cam for the control elements (20) is provided.
 21. Adevice according to claim 20, characterized in that with the exceptionof the transport path along the blow-molding wheel (2) as well as theregion of a uniform rotation of the preforms along the heating device(8), along the other regions of the transport path of the preformsthrough the device for blow-moldings radial cams for the controlelements (20) are provided.
 22. A device according to claim 11,characterized in that in the region of the heating device (8) atransport chain for moving the carrier devices (19) is used.
 23. Adevice according to claim 22, characterized in that the transport chainis extended linearly in at least some regions.
 24. A device according toclaim 22, characterized in that the transport chain envelopes anessentially rectangular base structure.